This workout is great to develop and strengthen the shoulders. You can do this exercise with both dumbbells and a straight bar. The smith machine is what is used also for this workout. This is a safer alternative for those who workout alone or have trouble with balance. Regardless you should always have a spotter if you are not comfortable with the workout or weight. It is also good to know that a free weight straight bar weights 45 pounds while a smith straight bar weights about 15-25 pounds.